This invention relates to digital and analog transmission of signals using noisy communication distribution facilities having severe punctuated noise occurring followed by changes in steady state noise level. It is particularly concerned with an algorithm and a process that will allow for optimization and increase of throughput of voice and data transmission over noisy link or wire networks. In one aspect it concerns access to premises through power line distribution facilities network, in-premises broadband services distribution and in-premises voice or data networks
In a noisy communication link environment where the transmission medium may change its noise level in a punctuated fashion (i.e., dramatically), there are intermediate steps in time in which the noise level of the transmission medium is relatively stable although not necessarily at a constant level of past stable noise levels. These stable noise levels occur in between the abrupt punctuated changes of noise level in the transmission environment.
Such noise level conditions of punctuated noise and in between stable noise levels may occur in many transmission environments. One environment which may be used for telephone communication within a local area and within a residence is the power wiring or power line environment. Examples of such impedance changes in the power line network may be due to operation or termination of operation of major appliances and other power usage equipment in the premises and are not predictable. When they occur as the equipment starts to operate, it operates for a given amount of time and then ceases to operate. The beginning and cessation of operation each causes a punctuated noise occurrence or a noise spike. In between the noise is stable but not necessarily at a consistent level compared with previous stable noise levels. Typically the time duration in which the change (i.e., turn on, turn off) was made is very short in duration (t0) and to the time duration of the stable noise level in which there are no significant changes is relatively long in duration as (t1). These changes occur in a short time to and that the duration of the time in which the changes are not strong is t1. In algebraic terms:
t1 greater than  greater than t0
In a power line network, for example, each of these punctuated noise occurrences introduces different subsequent semi-stable noise levels into the power wire network, and creates a different impedance load over the power line wire network. The punctuated noise depicts itself in many ways (i.e. reflections from the power line network), that have to be dealt with. Moreover, any combination between both noise sources created causes different levels of semi-stable noise, and different levels of attenuation of the power wires network in the premises.
A method and apparatus, according to principles of the invention, improves transmission quality of transmission media in a punctuated noise environment by terminating transmission during duration of punctuated large noise changes and alters network parameters, of the transmission media, to accommodate changes in level of stable noise conditions between punctuated large noise changes. Each stable noise level encountered is measured and its characteristics (i.e., level) is stored in a data base and associated network parameters (i.e., bit rates, bandwidth etc.) are changed accordingly and used to control or maintain quality of the transmission media.
An algorithm to allow for better utilization of the potential throughput of the transmission system under this environment detects a punctuated noise occurrence and halts transmission on the transmission media during that occurrence and then determines the appropriate parameters for optimal transmission during the next period of stable state noise. It is based on adaptation to the noise and to the transmission environment changes after detecting changes and on continuous operation when the changes are nominally low (i.e., a stable state of noise).
Another aspect of the invention is to record typical steady state noise characteristics and to use a transmission parameter set that is right for the appropriate steady state noise environment. This allows for minimal transmission of management information over the network, and reduces the time needed for the network modems to adapt to the new noise changes in the environment. When a system is simultaneously supporting voice and data, it is crucial to support the quality of service expected for voice conversation, and yet maintain ample bandwidth to support the ever-increasing data transmission demand. In accordance with the invention the usage of power line wire network (for example) is optimized for transmission of simultaneous voice and data on the same system.